Spinal fusion devices, systems and methods

ABSTRACT

According to some embodiments, a method of accessing an intervertebral space of a patient&#39;s spine in a minimally invasive manner compromises creating a passage from a posterior end of a pedicle of a vertebral member using a probe, advancing the probe through the pedicle and to a main body portion of the vertebral member, advancing the probe through a superior endplate of the vertebral member and into the intervertebral space and enlarging the passage using at least one tap to create an enlarged passage from a posterior of the pedicle to the intervertebral space. In some embodiments, the enlarged passage traverses at least three cortical layers of the vertebral member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 14/341,587 filed Jul. 25, 2014, which is acontinuation application of U.S. patent application Ser. No. 13/422,816filed Mar. 16, 2012 and issued as U.S. Pat. No. 8,790,375 on Jul. 29,2014, which claims the priority benefit under 35 U.S.C. § 119(e) of U.S.Provisional Patent Application No. 61/454,459 filed Mar. 18, 2011. Theentireties of all of the foregoing are hereby incorporated by referenceherein.

BACKGROUND Field

This application relates generally to devices, systems and methods forthe treatment of the spine, and more specifically, to access into anintervertebral space, spinal implants, pedicle screws, fixation systemsand related tools, systems and methods.

Description of the Related Art

Surgical approaches to the intervertebral space are utilized for avariety of indications and purposes, such as, for example, biopsy (e.g.,for evaluation of possible infection, other pathology, etc.), discectomy(e.g., for decompression of nerve roots, to prepare for subsequentfusion procedures, etc.), disc height restoration or deformitycorrection, disc replacement or repair (e.g., annular repair),discogram, gene therapy and/or other procedures or treatments.

Various approaches are currently used to access the interbody orintervertebral space of a patient's thoracic, lumbar and sacral spine.These include anterior approaches (ALIF) (e.g., open, mini-openretroperitoneal, etc.), lateral approaches (e.g., costotranversectomy,extreme lateral, etc.), posterolateral approaches (e.g., posteriorlumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion(TLIF), etc.) and axial approaches (e.g., axial lumbar interbodyfusion). Further, many minimally invasive and percutaneous approachesrely on radiographic landmarks with or without direct view to access atargeted interbody space. In addition, many, if not all, of thesecurrently used approaches require violation of the disc annulus toaccess the disc space.

Fusion surgery of the thoracic, lumbar and sacral spine is oftenperformed for a variety of indications, including degenerative jointdisease, deformity, instability and/or the like. Typically, traditionalfusion approaches involve relatively large, open incisions performedunder direct vision. Minimally invasive surgical techniques andcorresponding surgical implants have become more popular in an attemptto reduce morbidity and generally improve outcomes. Multiple variationsof percutaneous systems (e.g., pedicle screw and rod systems, facetscrew systems, etc.) have been developed. Such systems can allow forinstrumentation placement with fluoroscopic guidance (e.g., usingradiographically recognizable body landmarks) and/or other imagingtechnologies. Current fusion techniques, including those that utilizeopen and minimally invasive approaches, often require directvisualization. However, such techniques typically involve traversingspaces that are occupied by neural elements. Thus, these neural elementsneed to be retracted or otherwise moved during the execution of spinalprocedures that precede implantation (e.g., annulotomy, discectomy, discspace and/or vertebral endplate preparation, etc.). Retraction ofsensitive neural elements can also be required during the delivery of animplant to the spine.

These approaches typically require contact and retraction of nerve rootsand/or sensitive visceral organs, blood vessels and/or other sensitiveportions of the anatomy. Contact and retraction of these structures canplace them at risk, thereby increasing the likelihood of complicationsand damage to a patient. Accordingly, a need exists for improvedapproaches for spinal fusion and/or access to intervertebral spaces.

SUMMARY

According to some embodiments, a method of fusing a first vertebra to asecond vertebra, wherein the second vertebra is immediately adjacent andabove the first vertebra, comprises creating a passage from a posteriorend of a pedicle of the first vertebra through a superior endplate ofthe first vertebra, such that the passage extends into an intervertebralspace located generally between the first and second vertebrae. Themethod further comprises removing native tissue located within theintervertebral space by advancing a tissue removal tool through thepassage and selectively moving said tissue removal tool within theintervertebral space, and delivering at least one of an implant and agrafting material through the passage, wherein said implant or graftingmaterial is configured to promote fusion between the superior endplateof the first vertebra and an inferior endplate of the second vertebra.In some embodiments, the method comprises advancing a first bone screwthrough the passage, such that a distal end of the first bone screwextends at least partially into the intervertebral space.

According to some embodiments, a vertebral fusion system for fusing afirst vertebra to a second vertebra comprises a first bone screwpositioned through the first vertebra along a transpedicular passage ofsaid first vertebra, wherein the first bone screw extends from aposterior end of a pedicle of the first vertebra through a superiorendplate of the first vertebra, such that the passage extends into anintervertebral space located generally between the first and secondvertebrae, a facet implant positioned in a facet joint between the firstand second vertebrae and a connector coupling the first bone screw tothe facet implant to at least partially stabilize the first vertebrarelative to the second vertebra. According to some embodiments, thesystem further comprises a second bone screw positioned through thesecond vertebra. In some embodiments, the system comprises a rod orother connector connecting the first bone screw to the second bonescrew. In some embodiments, the system comprises at least one implantconfigured to be positioned between adjacent endplates of the first andsecond vertebrae. In one embodiment, the implant comprises an expandableimplant (e.g., a coiled implant, an inflatable implant, etc.).

According to some embodiments, the passage created through the firstvertebra is generally linear. In some embodiments, the method isperformed minimally invasively. In some embodiments, the implantcomprises an expandable implant (e.g., a coiled implant, an inflatableimplant, etc.). According to some embodiments, removing native materialcomprises removing disc material, material from an endplate of the firstvertebra and/or the second vertebra and/or the like. In someembodiments, the tissue removal tool comprises a curette, a brush, amovable ribbon and/or the like. In some embodiments, the tissue removaltool comprises an expandable head portion, wherein the expandable headportion is configured to assume a collapsed positioned duringadvancement through the passage and wherein the head portion isconfigured to selectively assume an expanded position within theintervertebral space.

According to some embodiments, the method additionally comprisesinserting a guidewire into the passage, wherein tools, devices and/orother materials are guided through the passage using the guidewire. Insome embodiments, the method further comprises inserting an accessdevice within the passage to facilitate the movement of tools or devicesthrough the passage. In one embodiment, the method further comprisesinserting a second bone screw through the second vertebra. In someembodiments, the method additionally comprises connecting the first bonescrew to the second bone screw (e.g., using a rod or other connector).In some embodiments, the second bone screw does not extend through anendplate of the second vertebra.

According to some embodiments, the method further comprises inserting afacet implant in at least one of the facet joints between the first andsecond vertebrae to fuse the first and second vertebrae at the at leastone of the facet joints. In some embodiments, the facet implant isconfigured to selectively distract adjacent surfaces of the first andsecond vertebrae. In some embodiments, the facet implant comprises oneor more teeth and/or other ratcheting members to facilitate thedistraction of the vertebrae. In some embodiments, the method furthercomprises removing at least some native tissue within the facet jointbefore inserting the facet implant in said facet joint. In someembodiments, removing at least some native tissue within the facet jointcomprises selectively moving a rasping device within said joint. In someembodiments, the method further comprises securing the first bone screwto the facet implant.

According to some embodiments, a method of fusing a first vertebra to asecond vertebra comprises creating a passage from a posterior end of apedicle of the first vertebra through a superior endplate of the firstvertebra, such that the passage extends into an intervertebral spacelocated generally between the first and second vertebrae, removingnative tissue located within the intervertebral space by advancing atissue removal tool through the passage and selectively moving saidtissue removal tool within the intervertebral space, advancing a firstbone screw through the passage, such that a distal end of the first bonescrew extends at least partially into the intervertebral space,inserting a second bone screw through the second vertebra and attachingthe first bone screw to the second bone screw.

According to some embodiments, a method of fusing a first vertebra to asecond vertebra comprises creating a passage from a posterior end of apedicle of the first vertebra through a superior endplate of the firstvertebra, such that the passage extends into an intervertebral spacelocated generally between the first and second vertebrae, removingnative tissue located within the intervertebral space by advancing atissue removal tool through the passage and selectively moving saidtissue removal tool within the intervertebral space, advancing a firstbone screw through the passage, such that a distal end of the first bonescrew extends at least partially into the intervertebral space andinserting a facet implant in at least one of the facet joints betweenthe first and second vertebrae to fuse the first and second vertebrae atthe at least one of the facet joints.

According to some embodiments, a method of accessing an intervertebralspace of a patient's spine in a minimally invasive manner comprisescreating a passage from a posterior end of a pedicle of a vertebralmember using a probe, advancing the probe through the pedicle and to amain body portion of the vertebral member, advancing the probe through asuperior endplate of the vertebral member and into the intervertebralspace and enlarging the passage using at least one tap to create anenlarged passage from a posterior of the pedicle to the intervertebralspace. In some embodiments, the enlarged passage traverses at leastthree cortical layers of the vertebral member.

According to some embodiments, the method additionally comprisespositioning a cannulated access device within the enlarged passage. Inone embodiment, the cannulated access device comprises a plurality ofexternal threads. In some arrangements, the method further comprisesproviding at least one tool through the enlarged passage and moving saidat least one tool within said enlarged passage in order to remove nativedisc material adjacent the target intervertebral space. In someembodiments, the at least one tool comprises a brush, an abrasive memberor surface and/or any other device.

According to some embodiments, the method further comprises creating asecond passage from a posterior end of a second pedicle of the vertebralmember using a probe, advancing the probe through the second pedicle andto a main body portion of the vertebral member, advancing the probethrough a superior endplate of the vertebral member and into theintervertebral space and enlarging the second passage using at least onetap to create a second enlarged passage from a posterior of the secondpedicle to the intervertebral space. In one embodiment, the secondenlarged passage traverses at least three cortical layers of thevertebral member.

According to some embodiments, the method further comprises passing atleast one tool through the passage and the second passage in order toremove native disc and/or other tissue of the patient. In someembodiments, the at least one tool is passed over a guidewire or cable,wherein the guidewire or cable is positioned through the passage and thesecond passage. In one embodiment, the method further includesdelivering an expandable implant into the intervertebral space throughat least one of the passage and the second passage. In one embodiment,the method additionally comprises delivering a structural implant intothe intervertebral space through at least one of the passage and thesecond passage.

According to some embodiments, the method further includes delivering adisc replacement device into the intervertebral space through at leastone of the passage and the second passage. In one embodiment, the methodfurther comprises delivering a medicine injection device (e.g., aninfusion pump, another device, etc.) into the intervertebral spacethrough at least one of the passage and the second passage. In someembodiments, the method further comprises delivering a disc samplingdevice and/or other biopsy device into the intervertebral space throughat least one of the passage and the second passage. In some embodiments,removed native tissue is removed through at least one of the passage orthe second passage for subsequent biopsy or other analysis. In oneembodiment, the method further comprises accessing a disc located withinthe intervertebral space for nucleus replacement, other non-fusionprocedures and/or any other purpose.

According to some embodiments, the method further includes delivering atleast one expandable implant within the intervertebral space. In someembodiments, the method additionally comprises expanding the at leastone expandable implant once said at least one expandable implant isdelivered to the intervertebral space. In one embodiment, the methodfurther includes delivering at least one material to the intervertebralspace. In some embodiments, the at least one material comprises agrafting material, putty or other filler material. In some embodiments,the method additionally comprises positioning a screw within theenlarged passage.

According to some embodiments, a pedicle screw configured for placementwithin a target vertebral member of a patient comprises a head and ashaft portion, wherein at least a portion of the shaft portion isthreaded, and wherein the pedicle screw is configured for placement froma posterior portion of a pedicle of the vertebral member to and througha superior endplate of the vertebral member. Further the pedicle screwis configured to extend through at least three cortical surfaces of thevertebral member. According to some embodiments, the head is of a fixedangle, uniaxial or polyaxial type. In one embodiment, the shaftcomprises a cortical thread pattern, a cancellous thread pattern and/ora combination thereof.

According to some embodiments, a method of accessing an intervertebralspace of a patient's spine in a minimally invasive manner compromisescreating a passage from a posterior end of a pedicle of a vertebralmember using a probe, advancing the probe through the pedicle and to amain body portion of the vertebral member, advancing the probe through asuperior endplate of the vertebral member and into the intervertebralspace and enlarging the passage using at least one tap to create anenlarged passage from a posterior of the pedicle to the intervertebralspace. In some embodiments, the enlarged passage traverses at leastthree cortical layers of the vertebral member.

In some embodiments, the method additionally includes positioning acannulated access device within the enlarged passage. In one embodiment,the cannulated access device comprises a plurality of external threads.In some embodiments, the method further comprises delivering at leastone expandable implant within the intervertebral space. In someembodiments, the method additionally includes expanding the at least oneexpandable implant once the at least one expandable implant is deliveredto the intervertebral space. According to some embodiments, the methodfurther comprises delivering at least one material to the intervertebralspace. In one embodiment, the at least one material comprises a graftingmaterial, putty or other filler material. In some embodiments, themethod additionally includes positioning a screw within the enlargedpassage.

According to some embodiments, a pedicle screw configured for placementwithin a target vertebral member of a patient comprises a head and ashaft portion, wherein at least a portion of said shaft portion isthreaded. The pedicle screw is configured for placement from a posteriorportion of a pedicle of the vertebral member to and through a superiorendplate of the vertebral member. In some embodiments, the pedicle screwis configured to extend through at least three cortical surfaces of thevertebral member. In some embodiments, the head is of a fixed angle,uniaxial or polyaxial type. In several embodiments, the shaft comprisesa cortical, cancellous and/or combination type thread pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentapplication are described with reference to drawings of certainembodiments, which are intended to illustrate, but not to limit, thepresent inventions. It is to be understood that these drawings are forthe purpose of illustrating concepts of the present inventions and maynot be to scale.

FIGS. 1A-1D illustrate various views of transpedicular openings througha vertebral member according to one embodiment;

FIGS. 2A-2D illustrate various views of the transpedicular openings ofFIGS. 1A-1D having guidewires passed therethrough;

FIGS. 3A-3D illustrate various views of the transpedicular openings ofFIGS. 1A-1D having taps or other opening enlargement devices positionedtherein;

FIGS. 4A-4D illustrate various views of the transpedicular openings ofFIGS. 1A-1D having cannulated access devices positioned therein;

FIGS. 5A-5D illustrate various views of one embodiment of a tissueremoval system positioned within the cannulated access devices of FIGS.4A-4D;

FIGS. 6A-6D illustrate various views of another embodiment of a tissueremoval system positioned within the cannulated access devices of FIGS.4A-4D;

FIGS. 7A and 7B illustrate different side views of a blunt, cannulatedrasping tool according to one embodiment;

FIG. 8A illustrates a perspective view of one embodiment of a curette orother disc tissue removal member configured to pass through a cannulatedaccess device or other opening and into an intervertebral space;

FIG. 8B illustrates a perspective view of another embodiment of a tissueremoval member;

FIG. 9A illustrates a side view of one embodiment of a brush or otherbristled device configured to remove disc material and/or other tissuefrom an intervertebral space;

FIG. 9B illustrates a side view of the brush of FIG. 9A in a collapsedposition;

FIG. 10A illustrates a side view of one embodiment of a tissue removaldevice configured to remove disc material and/or other tissue from anintervertebral space;

FIG. 10B illustrates a side view of the device of FIG. 10A in acollapsed position;

FIG. 11 illustrates a side view of one embodiment of a radiallyexpandable device configured to remove disc material and/or other tissuefrom an intervertebral space;

FIG. 12A illustrates a side view of one embodiment of a radiallyexpandable device configured to remove disc material and/or other tissuefrom an intervertebral space;

FIG. 12B illustrates a side view of the device of FIG. 12A in acollapsed position;

FIG. 13A illustrates a side view of an expandable implant positionedwithin a target interbody space, according to one embodiment;

FIGS. 13B and 13C illustrate side views of the implant of FIG. 13A incollapsed and expanded positions, respectively;

FIG. 14 illustrates a side view of an expandable implant positionedwithin a target interbody space according to another embodiment;

FIG. 15 illustrates a side view of an expandable implant positionedwithin a target interbody space according to yet another embodiment;

FIG. 16A illustrates a side view of an expandable implant positionedwithin a target interbody space according to still another embodiment;

FIGS. 16B and 16C illustrate the implant of FIG. 16A and thecorresponding delivery device at various stages of expansion;

FIGS. 17A-17D illustrate various views of pedicle screws secured to avertebral member through transpedicular openings according to oneembodiment;

FIG. 18A illustrates a side view of a facet joint implant having aratcheting design according to one embodiment;

FIG. 18B illustrates a top view of the facet joint implant of FIG. 18A;

FIGS. 19A-19D illustrate various views of a spinal fusion systemaccording to one embodiment;

FIG. 20 illustrates a side or lateral view of a spinal fusion systemaccording to another embodiment;

FIG. 21A schematically illustrates one embodiment of a pedicle screw;and

FIG. 21B schematically illustrates another embodiment of a pediclescrew.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A variety of examples described below illustrate various configurationsthat may be employed to achieve desired improvements. The particularembodiments and examples are only illustrative and not intended in anyway to restrict the general inventions presented herein and the variousaspects and features of such inventions.

According to some embodiments, the present application discloses variousdevices, systems and methods for accessing the intervertebral orinterbody space of a patient's spine and/or performing certainprocedures related to spinal fusion using minimally invasive surgery(MIS) techniques. As discussed in greater detail herein, theintervertebral or interbody space of the targeted portion of thepatient's spine is accessed and/or treated minimally invasively using,at least in some embodiments, a “transpedicular” approach. The terms“intervertebral space” and “interbody space” are used interchangeablyherein, and generally refer to the space, gap or region between adjacentvertebral members. By way of example, as illustrated in the variousviews of FIGS. 1A-1D, the intervertebral space 20 between adjacentvertebrae 10A, 10B can be accessed using one or more openings orpassages 16 created through one of the vertebrae (e.g., the lower of thetwo adjacent vertebrae in the depicted arrangement). In someembodiments, such openings or passages are created, accessed and/orotherwise use using MIS techniques or procedures. As shown in FIGS.1A-1D, in some embodiments, an opening 16 is initiated along or near aposterior portion of the vertebra or vertebral member 10B and isadvanced through the pedicle. The opening can include a generallyupwardly orientation so that it extends through at least a portion ofthe body portion of the corresponding vertebra. In some embodiments, asillustrated in FIGS. 1A-1D, the transpedicular opening 16 passes throughthe upper endplate 14B of the vertebra 10B.

As shown in FIGS. 1A-1D, the transpedicular opening 16 can be generallystraight or liner (e.g., along a single longitudinal line or path) fromthe posterior side of the pedicle to the upper endplate 14B of thevertebral member 10B. Accordingly, the need to create a non-linear(e.g., curved) pathway through the vertebra 10B is eliminated. This canprovide certain advantages to the surgeon performing a spinal fusionprocedure. For example, as discussed in greater detail herein, therequired instrumentation and tools used to create such a passage arerelatively simple. Relatedly, the corresponding surgical procedures andtechniques used by the surgeon are also relatively simple andstraightforward due to the linear or substantially linear orientation ofthe passage or accessway into the target intervertebral space.

With continued reference to FIGS. 1A-1D, a transpedicular passage oropening 16 can advantageously provide access to an intervertebral space20 using MIS techniques and methods. This can provide certain benefitsand advantages over existing approaches (e.g., open anterior approach,lateral approach, etc.). For example, the need to contact and movenerves and other sensitive organs, structures and other anatomicalregions surrounding the spine is reduced or eliminated. As a result, asurgeon can obtain access to one or more interbody spaces through arelatively simple and safe posterior approach. In some embodiments, asdiscussed in greater detail herein, such minimally invasive approachesare further facilitated by the fact that access to the interbody spaceis provided using a linear or substantially linear passage through aportion of the vertebral member. In general, the overall collateraldamage associated with the approaches disclosed herein is generallyreduced when compared to open approaches. For example, the skin incisionthrough which the MIS is performed is generally smaller than those usedin other approaches (e.g., methods in which tissue retractors are used,open surgery, etc.). Further, the MIS approaches disclosed hereinadvantageously allow concurrent proximity/access to the facet joints,which can be simultaneously fused or distracted for indirectdecompression of the neural foramen/lateral recesses. For example, asdiscussed in greater detail herein with reference to FIGS. 18A-19D, aspinal fusion system can comprise, at least in part, one or more facetjoint implants. Additionally, in some embodiments, this approach to theintervertebral/disc space does not require the compromising, incision,removal and/or any damage or harm to the disc annulus. The approach alsoallows for placement of a tricortical screw for enhanced fixationpurposes.

According to some embodiments, a surgical procedure involves thecreation of two transpedicular passages 16 in a targeted vertebra 10B.For example, as shown in FIGS. 1A-1D, a passage 16 can be made througheach of the pedicles P. Thus, in some embodiments, the passages 16 aresymmetrical or substantially symmetrical about the longitudinal axis ofa patient's spine. As discussed in greater detail herein, creating twotranspedicular openings 16 in a vertebra can enhance the ability of asurgeon to manipulate tools and/or other instruments within a targetinterbody space 20, to selectively deliver devices (e.g., implants)and/or other materials (e.g., bone grafting materials) into and/or outof the interbody space and/or to perform other tasks related to theinterbody space (e.g., to remove native disc material, to repair a disc,to biopsy or otherwise excise tissue, to prepare the vertebral endplatesand/or other tissues in advance of fusion and/or the like). However, inother arrangements, only a single transpedicular opening 16 can be madeto access a target intervertebral space. A spinal fusion system inaccordance with the various embodiments described herein can compriseone, two, three or more transpedicular openings 16, as desired orrequired.

As illustrated in the various views of FIGS. 2A-2D, one or moretranspedicular openings or passages 16 can be configured to receive aguidewire G. In some embodiments, one or more instruments, tools,devices and/or other items may be delivered to and/or from theintervertebral space over the guidewire G, as desired or required,thereby facilitating a particular surgical procedure. The size, length,materials of construction, flexibility and/or other characteristics ofthe guidewire G can vary, depending on the particular application oruse. For example, in some arrangements, the gauge of the guidewire G isbetween 16 and 22 (e.g., 16, 18, 20, 22), and the guidewire G comprisesstainless steel, titanium, vitallium and/or any other metal, alloy orother material. In other embodiments, however, the gauge of theguidewire can be smaller than 16 (e.g., 14, 12, 10, smaller than 10,etc.) or greater than 22 (e.g., 24, 26, 28, 30, greater than 30, etc.),as desired or required for a particular application or procedure.

The distal end of the guidewire G can be removably anchored within aportion of the anatomy to help ensure that instruments, tools and/orother devices are safely and properly delivered to and/or from thetarget intervertebral space 20. For example, in certain embodiments, asillustrated in FIGS. 2B and 2C, the guidewire G can be anchored within aportion of the patient's anatomy (e.g., in or near the inferior endplate15A of the adjacent vertebra 10A).

As discussed in greater detail herein, implants, instruments, toolsand/or other devices can be passed to and/or from a targetintervertebral space 20 minimally invasively with the assistance of theguidewire G and/or imaging technologies (e.g., fluoroscopy).Alternatively, such devices, tools and/or other items can be movedthrough a transpedicular opening 16 without the use of a guidewire G.The use of a guidewire G can assist in the accurate delivery of tools,implants and/or other devices through the passage, especially in aminimally invasive procedure. One embodiment of how a transpedicularpassage 16 is created within a patient's vertebral member is describedbelow.

According to some embodiments, in order to begin the surgical procedure,a surgeon makes bilateral, posterior incisions in the skin and fascia ofa patient. Alternatively, when only a single passage or accessway 16 isto be created to the target intervertebral space through the vertebra,the surgeon can make only a single incision. In still other embodiments,more than two (e.g., three, four, more than four, etc.) passages can becreated within a single vertebral member. Regardless of the number ofpassages, corresponding incisions through the skin and related tissuecan be generally small (e.g., short in length) and can be locatedimmediately distal and lateral to the pedicle P (e.g., at or near thejunction of the pars interarticularis and the transverse process). Next,a probe (e.g., trochar, other sharp-tipped probe, etc.) can be used toperform a blunt dissection through the patient's muscular layer adjacentan incision. According to some embodiments, such a dissection roughlyapproximates the avascular plane of the Wiltse approach.

According to some embodiments, the probe is then tamped into one of thepedicles P of the vertebra. For example, the trochar or other instrumentcan be placed at the “6 o'clock” position of the pedicle and tamped intothe pedicle cortex with a trajectory that is generally directed towardthe “12 o'clock” position (as illustrated in FIG. 1A). Such a trajectorycan advantageously permit the probe to exit the endplate 14B of thevertebra 10B at or near the junction of the posterior one-third and themiddle one-third of the endplate in lateral view. As illustrated herein,the path created by the probe (and thus, the path of the correspondingpassage or accessway through the vertebra) is generally linear orstraight. In other words, the longitudinal axis of the passage fallsalong a single line. As noted above, such a linear approach can simplifythe procedure of creating the passage. Further, the approach canadvantageously permit a surgeon to use simpler tools and instrumentationin order to perform the procedure. For example, the need for drills orother passage-creating devices or systems that are configured to turn,rotate or otherwise change direction within the vertebral member areeliminated. In any of the procedures disclosed herein, fluoroscopyand/or other imaging technologies can be used to ensure that the probe(e.g., trochar) or other instrument is accurately positioned andadvanced relative to the pedicle, endplate and other portions of thepatient's spine.

Advancement of the probe through the top endplate 14B of the vertebra10B can advantageously create a pathway from the posterior side of thepedicle P to the intervertebral space 20 located above the targetedvertebra 10B. Thus, access to the space 20 can be created using a MISapproach without the need for open surgery, tissue retractors, dilatorsand/or other more intrusive devices, systems and methods. According tocertain arrangements, the trochar or other sharp-tipped probe orinstrument is cannulated. Thus, a guidewire G (FIGS. 2A-2D) can beadvanced within the lumen or other opening of the instrument after theprobe has been advanced to the target intervertebral or interbody space20. As discussed above with reference to FIGS. 2B and 2C, the guidewireG can be anchored into or otherwise fixed to (e.g., temporarily,removably, etc.) the adjacent inferior endplate 15A of the cephaladvertebra 10A or any other portion of the patient's spine.

In some embodiments, as illustrated in FIGS. 3A-3D, after atranspedicular passage has been created using a trochar (or using anyother probe or instrument), one or more taps 40 are used toprogressively enlarge the passage. For example, a plurality (e.g., two,three, more than three, etc.) of incrementally larger taps or similardevices 40 can be sequentially placed within the passage 16 to increasethe diameter or other cross-dimensional size of the passage. Such taps40 can help ensure that the passage 16 is enlarged to a desired size ina safe and predictable manner (e.g., without threatening or otherwiseundermining the structural integrity of the vertebra being penetrated).According to some embodiments, the taps or other enlargement devices 40are cannulated, thereby allowing them to be moved over a guidewire G(e.g., FIGS. 2A-2D). The taps can vary in size, depending on thepatient's age, size, spinal condition, general physical condition andother characteristics of the spine being treated. Further, the quantityof taps needed and their incremental size (e.g., diameter) can varydepending on the procedure to be performed, the implants, tools,instruments and/or other devices or materials that will be deliveredthrough the passage (e.g., to or from the target interbody space) and/orany other factors or considerations. By way of example, in someembodiments, the outside diameters of the taps 40 vary between about 4mm and 10 mm.

According to some embodiments, after the widest (e.g., largest diameter)tap 40 has been removed from the vertebra 10B, as shown in FIGS. 4A-4D,a cannulated access device 50 can be positioned within the passage 16created by the probe (e.g., trochar) and/or the taps 40. Such acannulated access device 50 can extend completely, substantiallycompletely or only partially along the length of a transpedicularpassage 16 created within a target vertebra. The cannulated accessdevice 50 can include external threads or other engagement features thatassist in anchoring (e.g., removably or permanently) within thevertebra. For example, in embodiments of the access device 50 thatcomprise external threads, the device 50 can be advanced into (and/orremoved from) the passage 16 by rotation (e.g., like a screw). In otherarrangements, the cannulated access device 50 comprises one or moreother types of engagement features, such as, for example, teeth, prongs,recesses and/or the like, either in lieu of or in addition to threads.Alternatively, access device 50 can include a roughened surface and/orany other feature that helps secure it within the passage 16. In yetother embodiments, the cannulated access device 50 does not comprise anyexternal threads or other engagement features at all. As noted abovewith reference to creating a passage through the vertebral member, insome embodiments, the access device 50 is positioned using minimallyinvasive methods. The access device 50 can be permanent or temporary, asdesired or required by a particular application or procedure. In someembodiments, once a passage 16 has been created within the vertebra,various tools, devices and/or other members are selectively movedthrough (e.g., in or out) of the passage without the need for an accessdevice.

Regardless of the exact external characteristics of the access device50, in order to help ensure that the access device remains securelyaffixed within the passage 16 during subsequent procedures (e.g.,delivery of various devices, instruments, tools, materials, etc.), oneor more external portions of the access device 50 can form a generallytight fit with the adjacent internal surface of the passage 16. Forexample, as noted above, some arrangements of a cannulated access devicecan include threads and/or other engagement features along theirexterior surface. Alternatively, a tight tolerance between the outsideof the access device 50 and the internal surface of the passage 16 canbe used to provide a friction-fit connection. In other arrangements,adhesives, such as glues, bone cement and/or other materials, can beused to help secure the cannulated access device 50 within atranspedicular passage 16.

With continued reference to FIGS. 4A-4D, according to some embodiments,the proximal end of an access device 50 extends proximally of thepassageway 16 and the patient's pedicle P. Thus, a surgeon can easilyinsert and/or remove implants, instruments, tools and/or other devicesto and/or from the transpedicular passageway(s) 16, as desired orrequired by a particular procedure or protocol. In other words, thecannulated access device can extend rearwardly from the posterior end ofthe spine to facilitate a surgeon's access to passages 16.Alternatively, the access device 50 can be generally flush or recessedrelative to the posterior end of the transpedicular passage 16.

The inner diameter or other cross-sectional dimension of the cannulatedaccess device 50 can vary depending on the patient's anatomy, the sizeof the targeted pedicles P, the condition of the patient's spine and/orone or more other factors or considerations. Accordingly, the accessdevice 50 can be provided in a plurality of standard or non-standardsizes, shapes and/or other configurations.

Once the transpedicular pathway or passage 16 within the vertebra hasbeen created and the pathway has been adequately enlarged and protected(e.g., using taps, cannulated devices, access devices and/or othermethods or devices, such as those discussed herein, etc.), the guidewireG can be removed, leaving the lumen of the cannulated access device 50or simply the passage 16 (e.g., in arrangements where no access deviceis used) generally free of any obstructions. In some embodiments, theguidewire G is removed only after a cannulated access device 50 has beenproperly seated within the targeted vertebra (e.g., up to the endplatecortex of the vertebra). As a result, one or more procedures can besubsequently performed. For instance, as discussed in greater detailherein, the passage 16 can be used to remove anatomical tissue, fluidsor other materials (e.g., for biopsy, testing, other excisionprocedures, etc.), to remove native disc material (e.g., discectomy),for endplate preparation, to deliver implants, bone grafting agents,other fillers and/or other devices or materials, for interbodystructural graft placement, interbody distraction and/or for any otherpurpose. Further, as discussed in greater detail herein, the passage 16can be used to deliver and secure an appropriately sized fastener (e.g.,standard or non-standard pedicle screw, other fastener, etc.) to thecorresponding vertebra. In some embodiments, such a fastener cancomprise a spinal fusion system together with one or more otherfasteners (e.g., pedicle screws in adjacent vertebra(e), rods, otherconnectors, etc.), implants (e.g., facet joint implants) and/or thelike.

As noted above, a direct pathway into the adjacent interbody orintervertebral space 20 can be created through one or both of thepedicles of a vertebra 10A, 10B. In some embodiments, it is advantageousto provide transpedicular access to the interbody space 20 via bothpedicles in order to enhance the maneuverability of implants, tools,instruments and/or other devices therein. In arrangements involvingrelatively simple procedures (e.g., biopsy, delivery of a medicament,etc.), it may be desirable to provide only a single transpedicularpathway to the interbody space 20. Additional details regarding variousprocedures that could be performed using one or more transpedicularpassages are provided below.

Removal of Interbody Tissue

FIGS. 5A-5D illustrate different views of one embodiment of a system 100configured to at least partially remove native disc material and/orother tissue located within an intervertebral space 20 of a patient.This can be performed as part of a discectomy, a biopsy, a preliminarystep in advance of subsequent procedures or steps and/or the like. Asshown, a tissue removal system 100 can include one or more cuttingmembers 110, abrasive members 120, curettes and/or any other deviceconfigured to selectively excise, grasp and/or remove tissue. Suchtools, instruments and/or other devices can be placed into one or moretranspedicular passages 19 of a vertebra 10A, 10B, as desired orrequired. Thus, the tools, instruments and/or other devices can beadvantageously sized, shaped and/or otherwise configured to pass throughthe passage using minimally invasive techniques (e.g., MIS). Asdiscussed in greater detail herein, such tools and/or other devices canbe expandable and/or collapsible to facilitate delivery through thepassage. In any of the embodiments disclosed herein, a visualizationscope or other imaging member can be inserted within or near theinterbody space 20 being treated (e.g., via the transpedicular passages19, other openings, etc.) to advantageously provide a surgeon withvisual confirmation of the procedure being performed. In otherarrangements, external imaging tools, such as, for example, fluoroscopy,other x-ray-based technologies and/or the like, can be used to assistthe surgeon performing a procedure within or near the interbody space 20(e.g., vertebral body distraction, fusion, discectomy, screw or otherfastener insertion, etc.).

With continued reference to FIGS. 5A-5D, a cutting member 110, anabrasive member 120 and/or any other component of a tissue removalsystem 100 can include a proximal portion that is grasped andmanipulated by the surgeon. According to some embodiments, the removalsystem 100 comprises one or more actuators and/or other controls thatallow the surgeon to operate one or more features of the system, suchas, for example, movable blades or other cutting members, movableabrasive members (e.g., rotating or reciprocating abrading head) and/orthe like. In the arrangement depicted in FIGS. 5A-5D, the cutting member110 comprises scissor-like blades or other sharp surfaces that rotate orotherwise move relative to each other. Thus, a surgeon can actuate thecutting member 110 to excise target native disc and/or other tissuewithin or near the interbody area 20. Similarly, the abrading member 120can be used to target and remove disc material and/or other tissuewithin or adjacent the interbody space. Any other type of cutting and/orabrading member can be used, either in lieu of or in addition to thoseillustrated or discussed herein. For example, other mechanical devices(e.g., brushes, expandable members having sharp edges or features,etc.), laser technology, heat and/or other ablative-based systems can beused to remove, ablate, destroy, alter and/or otherwise affect tissuelocated within or near a target interbody space 20.

According to some embodiments, one or more removal members can be routedthrough a transpedicular passage 16 to capture and/or help move exciseddisc material, other tissue, fluids and/or other debris or materials outof the interbody space 20. For example, the removal member can include avacuum or suction line (e.g., in fluid communication with a vacuumsource), a grasping device and/or the like. In other arrangements, suchas those used in biopsy procedures, a removal member can be configuredto obtain a tissue sample, separate it from adjacent tissue and grasp itfor removal from the spine.

In other embodiments, a tissue removal system comprises an abradingmember or other device that is adapted to roughen or otherwise undermineat least a portion of an endplate in preparation for a fusion implant.The roughening of the endplate (e.g., which may include causing at leasta portion of the endplate to bleed) can promote and facilitateattachment of an implant and/or grafting material to the adjacentvertebral surfaces, thereby increasing the likelihood of success of aspinal fusion procedure.

As illustrated in FIGS. 6A-6D, in one embodiment, a tissue removal orroughening system 200 comprises two or more components 210, 220 that canbe selectively connected to each other within the interbody space 20.For example, the system 200 can include a grasped portion 210 and acorresponding retention portion 220, each of which is advanced to thetarget intervertebral space 20 through separate passages or openings 16.In one embodiment, the portions 210, 220 can be releasably connectedwithin the interbody space 20 (e.g., with the assistance of fluoroscopy,other imaging technology or tool, etc.). Once attached to each other,the different portions 210, 220 of the removal or roughening system 200can be moved as a unitary structure by manipulating the proximal ends ofeach separate component 210, 220. For example, the proximal ends of thecomponents 210, 220 can be directed in forward and rear directionswithin each of the passages 16 (e.g., including respective accessdevices 50 situated therein, if any) to move the attached distal ends ofthe components in a reciprocating manner within one or more regions ofthe interbody space 20. Thus, if the distal ends of the separatecomponents 210, 220 comprise cutting or abrading members and/orfeatures, native disc material, chondral or bone portion of vertebralendplates and/or other tissue within the interbody space 20 can beexcised, roughened, shaved and/or otherwise undermined, in accordancewith a desired procedure or method. In addition, a thin, flexible cablemay be passed through one passage (e.g., within one access device) intothe disc space and grasped and pulled back into the opposite passage(e.g., within the other access device). Then various flexible cannulateddisc removal and abrading tools may be passed over such a cable systemas part of the discectomy and/or disc space preparation procedure. Theflexible, cannulated tools can comprise wire brushes, other types ofbrushes (e.g., brushes having different materials and/or components),expandable balloons with or without roughened working surfaces and/orother varieties of tools or instruments, as desired or required for aparticular application or use.

FIGS. 7A and 7B illustrate different side views of one embodiment of arasped surface probe or tool 800 configured for placement through atranspedicular passage of a vertebral member. The tool 800 can becannulated or non-cannulated, as desired or required for a particularapplication or use. As discussed in greater detail below, such a probeor tool can also be used to treat a facet joint and/or any other portionof the spine as part of a spinal fusion system. As shown, the raspingtool or probe 800 can include a handle 810 along its proximal end. Anelongated shaft 820 can extend from the handle 810 toward the distal endof the probe 800. In some embodiments, as depicted in FIGS. 7A and 7B,the distal end of the probe 800 comprises a rasping or abrading head 830that is adapted to selectively remove disc material, cartilage, boneand/or other native tissue from the target interbody space and/oradjacent anatomical surfaces or portions. The head 830 can include oneor more abrading structures or features 834. For example, in someembodiments, the abrading structures 834 include a plurality ofprotruding members that generally extend radially outwardly (e.g.,directly outwardly, at any angle relative to the longitudinal axis ofthe tool 800, etc.). In other embodiments, other types of abradingstructures or features (e.g., recesses, sharp edges, etc.) are used,either in lieu of or in addition to those illustrated in FIGS. 7A and7B.

FIG. 8A illustrates one embodiment of a curette or other cutting tool1500 that is sized, shaped and/or otherwise configured to be selectivelydelivered through a passage of a vertebral member. As noted above, suchtools can be used to remove disc material from the target intervertebralspace, to abrade and/or remove at a portion of the inferior and/orsuperior endplates adjoining the space and/or remove any other nativetissue, as desired or required.

With continued reference to FIG. 8A, the tool 1500 can comprise a handleportion 1512 and a main shaft or elongate portion 1510 extendingdistally therefrom. As shown, a distal end of the shaft 1510 cancomprise a cutting head 1520. In some embodiments, the head 1520comprises a concave or other cup-shaped portion. The edges 1522 thatform the concave head can be generally sharp in order to facilitate theremoval of native tissue from a targeted portion of the interbody space.In other embodiments, the edge 1522 can be serrated and/or comprise oneor more cutting features or members. The curette or cutting tool 1500can be configured to fit within a passage (e.g., cannulated accessdevice) of the vertebra being treated. Thus, the tool 1500 can beadvantageously used as part of an overall minimally invasive approach.

FIG. 8B illustrates another configuration of a curette of cutting tool1500′ that is similar to the tool of FIG. 8A. As shown, the depictedembodiment comprises a different head design 1520′. Specifically, thehead 1520′ comprises an open middle portion. In other words, the head1520′ of the tool 1500′ does not include a closed cup portion. In otherembodiments, a different head design can be used for such a tool toaccommodate a specific cutting and/or tissue-removal goal, as desired orrequired. For example, in one embodiment, the tool can include two ormore head portions along or near the distal end.

As noted above, a brush or other bristled device can be deliveredthrough the passage of the vertebra and manipulated within the targetinterbody space to abrade and remove tissue (e.g., native disc, endplatematerial, etc.). One embodiment of such a brush 1600 is illustrated inFIGS. 9A and 9B. According to some embodiments, the brush 1600 is atleast partially collapsible (e.g., radially) to facilitate deliverythrough a passage created within the vertebra using a minimally invasiveapproach. FIG. 9A illustrates a side view of the brush or bristleddevice 1600 in a radially expanded position. The brush 1600 can comprisea proximal elongate portion or shaft 1610 and a distal bristled portion1620A comprising a plurality of rigid, semi-rigid and/or flexiblebristles. Any combination of bristles can be used to provide the desiredrigidity, flexibility, strength, durability, abrasiveness and/or otherproperties to the brush. The bristles can comprise one or more metals,alloys, plastics or other polymers and/or any other suitable materials.In some embodiments, at least some of the bristles comprise nickeltitanium (e.g., Nitinol) and/or other shape memory materials.

FIG. 9B illustrates the brush 1600 in a radially collapsed or contractedorientation. In some embodiments, the brush is configured to be movedinto such a lower profile orientation in order to facilitate itsdelivery through the passage of the vertebral member. Thus, the brushcan be passed into or out of the target intervertebral space of thepatient while in this radially collapsed position and expanded once itsdistal portion (e.g., the bristled head) has been properly positionedwithin the interbody space. According to some embodiments, the bristledportion 1620B is maintained in a radially collapsed position using anouter sheath or other sleeve (not shown) that can be slidably movedrelative to the bristles. In other embodiments, the bristles are adaptedto be selectively moved between radially collapsed and expandedpositions mechanically (e.g., by manipulating an actuator that iscoupled to the bristled portion) and/or by any other method or device.

Regardless of its exact design and other features, the brush 1600, onceproperly positioned within the targeted intervertebral space, can bemanipulated by the surgeon in order to capture, abrade and/or otherwiseremove disc material, endplate surfaces and/or other native tissue ofthe patient. In some embodiments, the shaft or elongate portion 1610 ofthe brush 1600 is at least partially flexible or steerable to permit thesurgeon to rotate or otherwise move the bristled portion to specificportions of the intervertebral space.

Another embodiment of a tissue abrading and/or removal device 1700 isillustrated in FIGS. 10A and 10B. As shown, the device 1700 comprises aproximal shaft or elongate portion 1710 and a distal head 1720. In someembodiments, the head portion 1720 is configured to be selectively movedbetween a collapsed position (FIG. 10B) and an expanded position (FIG.10A). As discussed herein in reference to other embodiments of suchtissue removal or preparation tools, the head 1720 can be maintained inthe radially collapsed or contracted orientation while the device 1700is moved within or out of the passage of the vertebral member during aminimally invasive procedure. The head can move between its radiallycollapsed and expanded positions using a sheath, sleeve or other outermember. In other embodiments, the head can be collapsed and/or expandedusing a mechanical actuator and/or any other device or method, asdesired or required.

With continued reference to FIG. 10A, when the device 1700 is expanded,the individual members 1722 that comprise the head 1720 can assume anyone of a number of radial positions. Any combination of members 1722 canbe used to provide the desired rigidity, flexibility, strength,durability, abrasiveness and/or other properties to the device 1700. Themembers 1722 can comprise one or more metals, alloys, plastics or otherpolymers and/or any other suitable materials. In some embodiments, atleast some of the members comprise nickel titanium (e.g., Nitinol)and/or other shape memory materials. Such a configuration of anexpandable head 1720 can be particularly effective in capturing andremoving native disc material from the targeted intervertebral space. Insome embodiments, the expandable members 1722 of the head 1720 compriserelatively sharp edges and/or end portions to enhance the tissuecapturing characteristics of the device. The members can also includeone or more other tissue capturing features, such as, for example,nodes, barbs and/or the like, to further enhance the effectiveness ofthe device.

Another embodiment of a tissue cutting or abrading device 1800 that iswell-suited for use in a minimally invasive approach is illustrated inFIG. 11. As shown, the device 1800 comprises a handle portion 1830 alongits proximal end. A shaft or elongate portion 1810 that extends from thehandle 1830 terminates in a cutting head along the distal end of thedevice. In some embodiments, the distal end of the shaft 1810 comprisesa window or opening 1816 that provides access to a lumen, opening orother interior portion of the device. Thus, a flexible ribbon or member1820 that is routed within such an inner lumen or opening of the devicecan be selectively urged out of the window 1816, in a direction awayfrom the shaft 1810. For clarity, FIG. 11 illustrates the ribbon orother member 1820 both in its collapsed orientation 1820B and in itsexpanded orientation 1820A (in phantom). In some embodiments, theflexible ribbon or other member 1820 comprises one or more metals,polymeric materials and/or any other suitable material. In someembodiments, the ribbon or other member 1820 comprises sharp edgesand/or other tissue abrading features or portions (e.g., barbs, ridges,cutting members, rasped portions, etc.) to facilitate removal of nativetissues.

With continued reference to FIG. 11, the device 1800 can comprise amovable lever or other actuator 1840 along its proximal end (e.g., nearthe handle 1830). In some embodiments, the actuator 1840 is coupled(e.g., mechanically) to the ribbon or other movable member 1820, suchthat manipulation of the actuator 1840 (e.g., proximally and distally,rotatably, etc.) moves the ribbon or other movable member 1820 betweenthe collapsed and contracted positions. Accordingly, as with othercutting, abrading, removal and/or preparatory tools disclosed herein,the device 1800 can be delivered through a passage created within avertebral member (e.g., a transpedicular passage) and into a targetedintervertebral space. In order to enable or facilitate delivery of thedevice 1800 through the corresponding passage of the vertebra, thedevice can be in the collapsed position (e.g., the ribbon or otherflexible member 1820B is positioned within an interior of the shaft1810). Once the distal portion of the device has been properly advancedwithin the targeted interbody space, the surgeon can manipulate thedevice so as to move the ribbon 1820 to the expanded position 1820A.Accordingly, the surgeon can rotate or otherwise manipulate the expandeddevice in order to cut, shave and/or otherwise excise disc material,endplate surfaces and/or other native tissue of the patient.

Another embodiment of a tissue cutting and abrading tool 1900 isillustrated in FIGS. 12A and 12B. The device 1900 is similar to the onedepicted in FIG. 11 and discussed above. For example, the device 1900comprises a handle portion 1930 and a shaft or elongate portion 1910extending distally therefrom. Further, the distal end of the elongateportion 1910 comprises one or more windows or openings 1916 throughwhich one or more ribbons or other flexible members 1922A can pass. Insome embodiments, as discussed herein with reference to the device ofFIG. 11, the ribbons or other movable members are configured to be movedbetween a collapsed position 1922B (FIG. 12B) and an expanded position1922A (FIG. 12A) by manipulating (e.g., moving longitudinally, rotating,etc.) an actuator 1940. As shown, such an actuator 1940 can bepositioned at or near the handle 1930 of the device.

In FIG. 12B, the device or tool 1900 comprises a total of two ribbons orother movable members 1922B that can be expanded outwardly throughcorresponding windows or openings 1916 of the elongate portion 1910.However, in other embodiments, the tool comprises fewer (e.g., one, asillustrated in FIG. 11) or more (e.g., three, four, five, more thanfive, etc.) ribbons or other movable members 1922, as desired orrequired by a particular application or use. Accordingly, as with othercutting, abrading, removal and/or preparatory tools disclosed herein,the device 1900 can be delivered through a passage created within avertebral member (e.g., a transpedicular passage) and into a targetedintervertebral space. In order to enable or facilitate delivery of thedevice 1900 through the corresponding passage of the vertebra, thedevice can be in the collapsed position (e.g., the ribbons or otherflexible members 1922 are positioned within an interior of the shaft1910). Once the distal portion of the device has been properly advancedwithin the targeted interbody space, the surgeon can manipulate thedevice so as to move the ribbons and/or other flexible or movablemembers to the expanded position 1922A. Accordingly, the surgeon canrotate or otherwise manipulate the expanded device in order to cut,shave and/or otherwise excise disc material, endplate surfaces and/orother native tissue of the patient.

The shape, size (e.g., width, thickness, etc.), materials and/or othercharacteristics of the ribbons or other movable members disclosed herein(e.g., with reference to FIGS. 11, 12A and 12B) can be selected toprovide the desired rigidity, flexibility, strength, durability,sharpness, cutting ability, abrasiveness and/or other properties to thetool. The ribbons can comprise one or more metals, alloys, plastics orother polymers and/or any other suitable materials. In some embodiments,at least some of the ribbons comprise nickel titanium (e.g., Nitinol)and/or other shape memory materials.

According to some embodiments, the transpedicular passage(s) 16 formedwithin a vertebra 10A, 10B can be used to deliver one or more materialsto a targeted interbody space 20. For example, grafting agents, otherbone forming materials, other filler materials and/or other substancesor devices can be transferred to the intervertebral space 20 through oneor more tubes or other conduits removably positioned within the passage16 and/or the cannulated access device 50. The delivery of such devicescan be advantageously performed using one or more minimally invasiveapproaches.

Interbody or Intervertebral Implants

As noted above, one or more implants can be selectively delivered to atarget intervertebral or interbody space 20 via a transpedicular passage16. According to some embodiments, such implants promote fusion of thetwo adjacent vertebral members. Such implants can also be used asdistraction members by helping to provide the necessary clearancebetween adjacent vertebrae, either in addition to or in lieu of beingused in a fusion or other stabilization procedure.

In some arrangements, in order to advance and position the implants to atarget intervertebral space in a minimally invasive manner, implants areconfigured to be selectively collapsed or otherwise contracted. In otherwords, the profile of the implants can be decreased for delivery througha transpedicular passage. Some non-limiting examples of such implantsare discussed herein with reference to FIGS. 13A-16C. However, any othertypes of expandable/collapsible or generally static implants or othermaterials can be delivered to a target intervertebral space.

FIG. 13A illustrates an anterior side view of one embodiment of anexpandable implant 300 positioned within an interbody space 20,generally between two adjacent vertebrae 10A, 10B. As shown, the implant300 can comprise an upper support 312, a lower support 314 and anarticulating arm 320 positioned therebetween. As noted above, theimplant 300 can be sized, shaped and/or otherwise configured to passthrough a passage created within the corresponding vertebra (e.g., thesuperior vertebra 10A or the inferior vertebra 10B) in order to positionthe implant within the target intervertebral space using a MIS approach.In some arrangements, upon proper deployment of the implant 300 afterdelivery to and within the interbody space 200, the upper support 312 isconfigured to be adjacent to the endplate 15A of the upper vertebra 10A,while the lower support 314 is configured to be adjacent to the endplate14B of the lower vertebra 10B. Further, when in the fully deployed orexpanded position (as illustrated in FIG. 13A), the connecting arm 320of the implant 300 can be permanently or releasably locked. Thus, theexpanded implant 300 can be adapted to maintain a desired separationdistance between its opposite supports 312, 314.

The quantity, size, shape, location, general configuration and/or othercharacteristics of the implant 300 can vary in accordance with aspecific patient, procedure, desired outcome and/or any otherconsideration. For example, implants 300 of various sizes and shapes canbe provided to allow a surgeon to provide a customized treatmentprotocol. In addition, the implant 300 can include one or moreadditional arms or struts 320 to provide additional strength, stabilityand/or other characteristics of the implant. In other embodiments, oneor more additional structures or devices can be delivered to theinterbody space (e.g., in one or multiple steps, depending on their sizerelative to the passage) and advantageously positioned between the upperand lower supports 312, 314. Such structures or devices canadvantageously provide additional stability and integrity to theimplant.

FIGS. 13B and 13C illustrate the implant 300 of FIG. 13A in differentstages of expansion or contraction. For example, the implant 300depicted in FIG. 13B is fully contracted or collapsed allowing it to bepassed within an opening (e.g., a transpedicular passage, a cannulatedaccess device, etc.). As shown, the fully contracted implant 300comprises a generally low profile to facilitate moving it throughrelatively small orifices. FIG. 13C illustrates the implant 300 in apartially expanded position, in which the upper and lower supports 312,314 include some vertical separation. According to some embodiments, theimplant can be selectively expanded, and thus, the upper and lowersupports 312, 314 can be spaced from each other, by rotating one of thesupport members (e.g., the upper support member 312) relative to theother support member (e.g., the lower support member 314). Thus, oncethe expandable implant 300 has been delivered to the interbody space andproperly positioned relative to the adjacent vertebrae, one or moretools can be used to selectively expand the implant 300. In the depictedarrangement, such expansion can be accomplished by moving the uppersupport 312 in a direction generally depicted by arrow 330.Consequently, the connecting arm 320 can rotate from a generallyhorizontal orientation to a more vertical orientation, eventuallylocking the implant 300 into the fully-expanded position (e.g., asillustrated in FIG. 13A).

Any of the implants disclosed herein, including the embodimentillustrated in FIGS. 13A-13C, can be moved between a contracted orcollapsed position and an expanded position (and/or vice versa) using anactuator. Such an actuator can be mechanical, pneumatic, electricaland/or the like. By way of example, the mechanical implant of FIGS.13A-13C can be expanded and/or contracted using a push/pull rod, wire oranother mechanical connector. Such connectors can be coupled to a lever,button, switch, foot pedal or other actuator that a surgeon canmanipulate to expand and/or contract the implant 300. As noted above, insome embodiments, the implant 300 is configured to “lock” or remain inthe deployed position once it has been fully expanded. This can helpensure that the upper and lower support member 312, 314 will not becompromised following implantation. Alternatively, the implant can beselectively contracted or collapsed following implantation for removalfrom the anatomy (e.g., through a transpedicular passage, anotheropenings, etc.). Such collapse can be preceded by an “unlocking” of theimplant or other step that generally safeguards against the unintendedundermining of the implant.

FIG. 14 illustrates another embodiment of an expandable implant 400configured for placement within a target interbody space 200. As shown,the implant 400 can comprise one or more expandable coils, cables orother members. Such coils or other members 400 can be delivered into theintervertebral space 200 through a transpedicular opening using aminimally invasive approach, while in a coiled or generally contractedstate. Once the implant 400 is released into the larger interbody space200, it can advantageously expand thereby occupying at least a portionof the space 200. If an appropriate amount and/or quantity of coiled orexpandable materials and/or members are delivered to the interbody space200, the implant 400 can provide sufficient structural support tomaintain (or, in some embodiments, even increase) a desired distancebetween the adjacent vertebrae 10A, 10B. In some embodiments, the coilcomprises nickel titanium (nitinol), another shape memory material,other resilient materials and/or the like. In some embodiments, thecable or other coiled member is delivered within a removable sheath,thereby allowing such a member to remain within a contracted orcollapsed state during delivery. As discussed with reference to otherembodiments herein, an expandable coil implant and/or any other implantpositioned within an intervertebral space can be supplemented byadditional structures, reinforcing members, fillers (e.g., cement,grafting materials, etc.) and/or the like, as desired or required.

With reference to FIG. 15, an implant can comprise an inflatable orfillable balloon 500, expansion structure and/or other expandablemember. The expandable member 500 can be delivered through atranspedicular passage when deflated or contracted and can besubsequently inflated or otherwise expanded once properly positionedwithin the interbody space 200. The implant 500 can be expanded usingone or more fluids (e.g., air, other gases, liquids, solidifying agents,other mixtures or substances and/or like) through a fill tube which isrouted through a passage within the vertebra (e.g., transpedicularpassage) and which can be selectively placed in fluid communication withthe interior of the implant 500. The implant 500 can include one or morevalves and/or other flow control devices or features to regulate theflow of materials into and/or out of the interior of the implant 500,thereby controlling the level of expansion and contraction. Such aninflatable or otherwise expandable implant 500 can comprise one or morepolymeric, elastomeric, metallic and/or other materials suitable forimplantation into a patient's anatomy. In some embodiments, one or moreelectrodes and/or other items can be positioned along the outside of theballoon or other expandable member, allowing the clinician toselectively treat or remove tissue within or near the interbody space(e.g., ablate, heat, cool, etc.).

Another mechanically-actuated implant 600 configured to be deliveredinto an intervertebral space 200 is illustrated in FIGS. 16A-16C.Similar to the arrangement discussed herein with reference to FIGS.13A-13C, the depicted implant can selectively transition from acontracted or delivery state (FIG. 16B) to an expanded state (FIGS. 16Aand 16C). According to some embodiments, the implant 600 is removablyattached to the distal end of a delivery instrument 610, which isconfigured to position the implant 600 into the target intervertebralspace 200 (e.g., via a transpedicular passage or other opening). Such aninstrument 610 can include a slidable rod or other connector configuredto expand and/or contract the implant 600. In other embodiments, theinstrument 610 comprises pituitary-style scissors or another similardevice having an actuator (e.g., handle) that allows a surgeon to expand(and/or contract) the implant 600 after delivery to the desired locationwithin an intervertebral space 200. For example, the proximal end of theinstrument 610 can include two scissor-like portions that are opened andclosed to change the orientation of the implant 600. Alternatively, asnoted above, one or more other types of actuation devices or featurescan be used to expand or contract the implant 600, such as, for example,a pull-rod system, a pneumatic device, an electric device and/or thelike.

With continued reference to FIG. 16B, after the implant 600 has beenpositioned within the interbody space 200, it can be expanded so thatits vertical profile increases (e.g., to extend, at least partially,between adjacent vertebra 10A, 10B). In some embodiments, the implant600 is configured to lock in the expanded position, ensuring that itwill not be undermined following implantation. In other arrangements,the implant 600 can be selectively contracted following implantation, asdesired or required.

As shown in FIGS. 16A-16C, the implant 600 can include two or moreseparate portions 620 (e.g., segments, leafs, etc.) that are joined toeach other using a hinge 622 or other connection. Thus, in someembodiments, such separate portions 620 can be rotated, translated orotherwise moved relative to each other in order to expand and/orcontract the implant 600. For example, in the depicted arrangement, thesegments 620 are configured to rotate in generally opposite directions(e.g., as represented by arrows 630, 632) upon actuation of the implant600. As a result, the implant 600 can lockingly or releasably assume agenerally vertical orientation as shown herein. As illustrated in FIG.16C, once the implant 600 has been expanded, the correspondinginstrument 610 can be detached from the implant 600 (e.g., using one ormore actuation devices located on the proximal end of the instrument600) and the instrument 610 can be easily removed from the anatomy(e.g., through a transpedicular passage or opening). As discussed withreference to other embodiments herein, an expandable implant and/or anyother implant positioned within an intervertebral space can besupplemented by additional structures, reinforcing members, fillers(e.g., cement, grafting materials, etc.) and/or the like, as desired orrequired.

Tri-Cortical Screws

According to some embodiments, a bone screw and/or other fastener can beplaced within a transpedicular passage (e.g., as discussed above) orthrough a similar pathway typically created by a passage within thevertebral member. As a result, the screw can pass through threedifferent bone cortices. Specifically, in some embodiments, the screwpasses through the cortex at the pedicle entrance (e.g., along or nearthe posterior side of the pedicle), the cortex of the pedicle shaft andthe cortex of the vertebral endplate. Consequently, such a screw can bereferred to as a tri-cortical screw, and the resulting securement astri-cortical fixation.

The use of such tri-cortical screws can provide enhanced fixation and/orone or more other benefits and advantages. For example, tri-corticalfixation can be advantageously associated with higher pull-out strength,as the screw/bone interface is less likely to be undermined when threedifferent cortices are transversed or crossed. Accordingly, these typesof screws can provide a more stable fixation than traditional pediclescrew systems.

In some embodiments, tri-cortical screws are fully threaded with acortical (cortex), cancellous or combination (e.g., cortical andcancellous) thread type screw pattern. However, the characteristics oftri-cortical screws can vary, in accordance with a specific procedure orprotocol. For example, a screw can comprise threads that extend onlypartially along its length. Further, tri-cortical screws can includeother types of thread patterns (e.g., standard, cancellous,transfixation, etc.), either in lieu of or in addition to cortex typethreads and/or features, as desired or required. In addition, asdiscussed in greater detail below, the type of screw head can vary,depending on the specific application or use. For instance, the screwhead can be of the fixed angle, uniaxial or polyaxial type. In otherembodiments, the screw comprises a tulip-head pedicle screw configuredto receive a rod or other component of a stabilization system.

According to some embodiments, the transpedicular or other types ofpedicle screws used with the various embodiments of the spinal fusionsystems and methods disclosed herein can have one or more varyingcharacteristics along their length. For example, as illustratedschematically in FIG. 21A, in one embodiment, a pedicle screw Scomprises a proximal section A that has a different thread pattern thata distal section B. For example, the proximal section A can include acancellous thread pattern while a distal section comprises a corticalthread pattern. In some embodiments, the cancellous thread patternlength (section A) comprises approximately 50% to 70% (e.g., about 50,52, 54, 56, 58, 60, 62, 64, 66, 68, 70%, percentages between theforegoing values, etc.) of the length of the screw. Thus, in such aconfiguration, the cortical thread pattern length (section B) comprisesapproximately 30% to 50% (e.g., about 30, 32, 34, 36, 38, 40, 42, 44,46, 48, 50%, percentages between the foregoing values, etc.) of thelength of the screw. In other embodiments, however, the cancellousthread pattern length (section A) comprises less than about 50% (e.g.,about 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50%, percentages between theforegoing values, etc.) or greater than about 70% (e.g., about 72, 74,76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100%, percentagesbetween the foregoing values, etc.) of the length of the screw.Accordingly, in such embodiments, the cortical thread pattern length(section B) comprises less than about 30% (e.g., about 0, 2, 4, 6, 8,10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30%, percentages between theforegoing values, etc.) or greater than about 50% (e.g., about 50, 55,60, 65, 70, 75, 80, 85, 90, 95, 100%, percentages between the foregoingvalues, etc.) of the length of the screw. In some embodiments, the screwS comprises a cancellous portion (Section A) that is approximately equalin length as the cortical portion (Section B).

As noted above, the use of a varying thread pattern along the length ofthe pedicle screw S can promote more enhanced connection between thescrew and the vertebral member or portion thereof (e.g., pedicle,endplate cortex, interior body of vertebra, etc.) through which thescrew is passed. For example, the screw 700 disclosed herein withreference to FIGS. 17A-17D is configured to pass through the superiorendplate of the lower vertebra 10B. Thus, having a cortical threadpattern along the distal end of the screw can create a stronger and moresecure fixation of the screw within the vertebral member. In otherembodiments, such as the pedicle screw P illustrated in FIG. 20, it maybe advantageous to use a screw that includes a cancellous thread patternalong its distal end, as that portion of the screw will terminate withinthe cancellous portion of the vertebra's interior body. Thus, in someembodiments, a pedicle screw comprises a cancellous thread pattern alongits distal end. The proximal thread pattern can be either cancellous,cortical and/or any other pattern, as desired or required. For example,for the pedicle screw P illustrated in FIG. 20, it may be advantageousto have a cortical thread pattern along its proximal end, because thatportion of the screw will be located through the cortical surface of thepedicle (e.g., thereby providing for a more enhanced fixation of thescrew along its proximal end).

In other embodiments, as illustrated schematically in FIG. 21B, thediameter of the screw (e.g., the outside diameter of the threads, theinside diameter of the threads, etc.), can vary along the length of thescrew S′. Such a configuration can be used irrespective of threadpattern. Thus, a proximal section of the screw S′ (Section C) caninclude a larger diameter, while a distal section of the screw (SectionD) comprises a relatively smaller diameter. According to someembodiments, the diameter of Section C can be approximately 0 to 30%(e.g., 0, 5, 10, 15, 20, 25, 30%, percentages between the foregoingvalues, etc.) larger than the diameter of Section D. However, in otherembodiments, the diameter of the larger diameter section (Section C) canbe more than about 30% greater (e.g., 30, 35, 40, 45, 50, more than 50%,etc.) than the diameter of the smaller diameter section (Section D), asdesired or required for a particular application or use. In still otherembodiments, the proximal portion of the screw S′ (Section C) has adiameter that is smaller than the distal portion (Section D).

As discussed above with reference to FIG. 21A, the ratio of the lengthof Section C to the length of Section D can vary, as desired orrequired. Further, the thread pattern associated with each of Sections Cand D can be customized in accordance with a particular, protocol,procedure or application. For example, in some embodiments, the proximalportion of the screw S′ (Section C) comprises a cancellous threadpattern, while the distal portion of the screw S′ (Section D) comprisesa cortical thread pattern. In other embodiments, the proximal portion ofthe screw S′ (Section C) comprises a cortical thread pattern, while thedistal portion of the screw S′ (Section D) comprises a cancellous threadpattern. In yet other embodiments, the entire length of the screw S′(both Sections C and D) comprises either a cancellous or a corticalthread pattern.

One embodiment of a tri-cortical screw 700 secured within a vertebra 10Busing a transpedicular approach is illustrated in FIGS. 17A-17D. Asshown, the screw 700 can be advanced through the pedicle toward andthrough the superior endplate 14B of the vertebral member 10B. In someembodiments, the pathway of the screw 700 is identical to that used tocreate a passage within the vertebral member. In fact, in someembodiments, the screw is simply inserted within and through the sametranspedicular passage used to access the intervertebral space, asdiscussed in greater detail above. In some embodiments, the outsidediameter of the screw or other fastener 700 is similar or slightlylarger than the insider diameter of the passage through the vertebralmember. This can help ensure that the screw is properly secured withinthe passage and that it will not become loose or dislodged afterimplantation. By positioning the screw or other fastener 700 through thesame transpedicular passage that is used to access a targetintervertebral space, collateral damage to the corresponding vertebraeis reduced or minimized, as the need for a separate opening through thevertebrae is eliminated. In other arrangements where a passage throughthe vertebral member has not been created, the screw or other fastenercan be similar or substantially similar to that of the transpedicularpassages or other openings discussed above with reference to FIGS.1A-6D.

The screw 700 can be placed within a targeted vertebra 10B under directvision using a minimally invasive (e.g., MIS) open, mini-open,arthroscopic or any other approach. For example, in keeping with theoverall theme and advantages provided by the various embodimentsdisclosed herein, the screw can be positioned within the targetvertebral member minimally invasively, thereby eliminating the need toperform more complicated and risky tissue retraction/distractiontechniques and/or the like. In some arrangements, the tri-cortical screwor other fastener 700 can be delivered through a tube/narrow retractor.In other embodiments, the pedicle screw 700 can be placed within thetarget pedicle P of the vertebra 10B percutaneously, over a guidewire,using fluoroscopic guidance (or with the assistance of some otherimaging technology) and/or using any other tool, technique or approach.For instance, the screw 700 can be guided through the vertebra using aguidewire G situated within a transpedicular passage (e.g., see FIGS.2A-2D).

As noted above, the screw 700 can include any one of a variety of headtypes, such as, for example, fixed angle, uniaxial or polyaxial. Withdirect vision, a rod (not shown) can be directed across the screw heads720 of the various pedicle screws 700 that have been secured to variousvertebrae of a patient's spine. For example, as discussed in greaterdetail below, the screw 700 can be one component of a spine fusion andstabilization system. The screw 700 can be coupled to and fastened with(e.g., using a rod, another direct or indirect connection or joint,etc.) to another pedicle screw or fastener (e.g., secured to one or moreother vertebrae), to a facet fixation implant and/or the like. In someembodiments, a rod or other fixation component can be directed acrossthe screw heads from the distal screw of the fixation system to theproximal screw. In some embodiments, the head of the pedicle screw 700is not configured to receive a rod or other component of a fixationsystem. In addition, the pedicle screw 700 can be cannulated ornon-cannulated, as desired or required. A cannulated screw can be guidedthrough a transpedicular passage or opening over a guidewire, asdiscussed herein.

Further, the thread pattern type, size, orientation and/or other detailsof the screw or other fastener 700 can vary, as desired or required. Insome embodiments, the screw 700 comprises a cortex type pattern acrossall or substantially all of its length. Alternatively, the threadpattern can be of a different type and/or can extend only partiallyalong the shaft of the screw, in accordance with a specific applicationor use.

According to certain embodiments, a screw inserter can be used to securea pedicle screw 700 to a vertebra 10B using atranspedicular/tri-cortical approach, as discussed herein. In sucharrangements, the screw inserter can be of sufficient length so as toprotrude outwardly form the patient's access wound, even when fullyseated within the vertebra. This can permit the screw inserter to serveas a reference point or landmark to assist in guiding a rod or othercomponent of a fixation system across the various pedicle screw heads.

Screws secured using the transpedicular/tri-cortical approach disclosedherein can be used as a part of a standard posterior fixation ofvertebrae (e.g., in a primary thoracic, lumbar and/or sacral fusion). Insome embodiments, the pedicle screws discussed herein, or alternativesthereto, are inserted into the corresponding vertebrae with theassistance of standard or non-standard instrumentation. In addition, asapplies, for example, to all unicortical versus bicortical screwfixation, the use of such tri-cortical pedicle screws can providestronger pull-out strength fixation in all patients, including patientswith various degrees of osteopenia/osteoporosis. Further, because oftheir higher pull-out strength, such screws can help salvage loosenedscrew holes from a pseudoarthrosis that requires reinstrumentation,(e.g., instead of simply using a much larger diameter screw). In otherembodiments, a tri-cortical pedicle screw can comprise a transfixationscrew positioned across the disc or interbody space 200. Thus, the screw700 can extend into the cephalad vertebral endplate 15A.

Facet Joint Preparation and Implants

According to some embodiments, one or more facet joints are prepared forreceiving one or more implants and/or other items therein. Such implantscan promote fusion of the facet joint and/or provide distraction betweenadjacent vertebrae. As discussed in greater detail herein, the fusion ofthe facet joint can be used, either alone or in combination with anotherspinal fusion system or procedure, to stabilize and/or fuse a portion ofa patient's spine or otherwise treat a particular spinal defect orailment. According to some embodiments, access to the facet joints,preparation of the joints, delivery of one or more implants and/or otherrequired steps are advantageously performed using minimally invasiveapproaches.

In some arrangements, in order to access the facet joints of a targetedportion of the spine, bilateral, posterior incisions are made throughthe skin and fascia of the patient. In some embodiments, such incisionsare generally short and are located immediately distal and lateral tothe pedicles (e.g., at or near the junction of the pars and transverseprocess) of the inferior vertebral body at the proposed fusion level.The surgeon can then use a generally blunt and flat probe to perform ablunt dissection through the muscular layer of the patient. In someembodiments, the probe is cannulated so that a guidewire and/or anyother appropriately sized device or item can be selectively passedtherethrough. In some arrangements, dissection through the patient'smuscle layer generally approximates the avascular plane of the Wiltseapproach.

Once the patient's muscle layer has been dissected, the probe can bedirected toward the distal/inferior aspect of the facet joint and tampedtherein. In some embodiments, the probe is tamped approximatelytwo-thirds of the way cephalad-anterior into the joint. Further,according to some arrangements, anteroposterior (AP) fluoroscopy isadjusted to approximately 15 to 20 degree oblique (e.g., depending onthe level of the thoracic or lumbar spine facet joints) to assist withthe advancement of the probe into the facet joint. The position of theprobe can be confirmed by the oblique AP and lateral views. For example,using a lateral view, the surgeon can use a probe trajectory thatmaintains the probe tip posterior to the neural foramen. Once the probehas been adequately advanced into the joint, a guidewire can be passedthrough the lumen or opening of the cannulated probe and secured to theproximal end (e.g., proximal one-third) of the facet joint. In someembodiments, the guidewire comprises a sharp and/or a threaded tip tofacilitate securement to the joint. The guidewire can be fixed orotherwise secured to the proximal third of the joint using aninterference fit, by penetration into the cephalad aspect of the facetjoint or joint capsule and/or via any other attachment method, asdesired or required.

Once the guidewire has been secured relative to the facet joint, thecannulated probe can be removed from the anatomy. In some embodiments,the chondral surfaces of the superior and/or inferior facet surfaces ofthe joint are then at least partially removed. For example, a raspingtool or other tool or device having one or more abrading surfaces can beinserted within the facet joint and moved in a manner that causesremoval of the cartilage from one or more portions of the joint. Inarrangements where a guidewire extends into the facet joint, acannulated rasping or other abrading tool can be used. Alternatively,however, such a rasping or abrading tool does not need to be cannulated.Accordingly, the tool can be directed into the facet joint without theassistance of a guidewire, as desired or required by a particularprotocol.

With reference back to FIGS. 7A and 7B, a probe or tool 800 having arasping surface can be selectively placed within a facet joint. Asshown, the rasping tool or probe 800 can include a handle 810 along itsproximal end. An elongated shaft 820 can extend from the handle 810toward the distal end of the probe 800. In some embodiments, as depictedin FIGS. 7A and 7B, the distal end of the probe 800 comprises a raspingor abrading head 830 that is adapted to selectively remove cartilage,bone and/or other tissue from anatomical surfaces. The head 830 caninclude one or more abrading structures or features 834. For example, insome embodiments, the abrading structures 834 include a plurality ofprotruding members that generally extend radially outwardly (e.g.,directly outwardly, at any angle relative to the longitudinal axis ofthe tool 800, etc.). In other embodiments, other types of abradingstructures or features (e.g., recesses, sharp edges, etc.) are used,either in lieu of or in addition to those illustrated in FIGS. 7A and7B.

In some embodiments, the rasping tool 800 comprises one or more interiorlumens 840. Thus, a user can advance the tool 800 into a targeted joint(e.g., a facet joint) over a guidewire, as discussed in greater detailherein with reference to other embodiments. In other arrangements,however, a rasping tool can be positioned within a facet joint and/orselectively manipulated therein without the assistance of a guidewire.For example, the tool 800 can be accurately positioned within a jointwith the assistance of imaging technology (e.g., fluoroscopy), eitherwith or without the assistance of a guidewire, as desired or required.

According to some embodiments, the rasping tool 800 is tamped within thefacet joint (e.g., approximately two-thirds deep into the joint). Oncewithin the joint, the tool 800 can be manipulated (e.g., moved into andout of the joint) in order to accomplish a desired abrasion effect onthe adjacent chondral surfaces of the joint. In some arrangements, therasping tool 800 is used to remove, at least partially, chondral layersof the superior and/or inferior facet surfaces and/or to cause the facetjoint to bleed. As discussed in greater detail herein, such preparationof the chondral surfaces of a facet can help promote the subsequentfusion of the treated joint. Depending on the exact configuration of therasping or abrading tool used, the desired level of abrasion of thechondral surfaces and/or one or more other considerations, the tool canbe moved into and out of the facet joint either once or multiple times(e.g., two times, three times, four times, fives times, more than fivetimes, etc.).

Once the facet joint has been adequately abraded and/or otherwiseprepared, the abrading tool 800 can be removed (e.g., by retracting thetool over the guidewire). In some embodiments, with its adjacent facetsurfaces adequately abraded, the facet joint can then be permitted tofuse. Facet joint fusion can be accomplished through prolonged contactbetween the facet subchondral decorticated bony surfaces. Alternatively,one or more screws, other fasteners, other securement devices orfeatures, implants and/or the like can be inserted within or near thefacet joint to facilitate the fusion process. Regardless of whichapproach is used, relative immobilization of the adjacent facet surfacesmay be desired to properly complete the fusion procedure and to ensurethat it will not be compromised after the procedure.

According to some embodiments, one or more implants are positionedwithin a target facet joint, either with or without the use of aguidewire. Fluoroscopy and/or other imaging tools or technologies can beused to accurately and safely position an implant into a joint (and/orsubsequently manipulate the implant within that joint), as desired orrequired. For instance, in one embodiment, an implant is placed over aguidewire and advanced into a facet joint using the confirmation of APand lateral fluoroscopy. According to some embodiments, a standard ornon-standard implant inserter is used to advance an implant into thefacet joint. In some arrangements, the inserter or similar deviceincludes one or more drill guides configured to assist the surgeon inaccurately penetrating one or more portions of the inferior and/orsuperior facet surfaces during a subsequent drilling procedure.

By way of example, the drill guide on the inserter device can be offsetby approximately 2 to 5 mm medial and lateral to the facet joint plane.However, the offset, spacing and/or other details related to the drillguide can vary, as desired or required by a particular procedure orprotocol. With the assistance of drill guide(s), imaging technologies(e.g., fluoroscopy) and/or any other guiding device or method, a drillcan be used to create one or more passages through the bones thatcomprise the facet joint. In one embodiment, a drill is driven into theinferior facet subchondral bone with parallel trajectory to the facetjoint plane using an AP or oblique fluoroscopy view. The trajectory ofthe drill, and thus the passage that is created therethrough, can begenerally in line with the facet joint and pars interarticularis using alateral fluoroscopy view. In some arrangements, the trajectory remains,at all times, posterior to the neural foramen. In some embodiments, anawl-tipped type drill is used to penetrate the inferior facetsubchondral bone. Further, the drill can be either hand-driven orpower-driven, as desired or required. Any other type of bone drill orother advancement device can be used.

After creating the desired passage(s) through the bone(s) of theinferior facet, the drill can be removed. Subsequently, a screw or otherfastener can be advanced into the target facet and positioned within apassage created by the drill. In some embodiments, a screw is passedinto the inferior facet through the medial drill guide to secure animplant to the proximal vertebrae. In other arrangements, a screw can bepassed into the superior facet through a corresponding guide and/oropening, either in lieu of or in addition to an inferior screw.Regardless of the exact securement details, an implant can be adequatelymaintained within the targeted facets to promote fusion of such joint.In some embodiments, bone grafting materials, bone cement and/or thelike can be used between and/or near the facet joint to further promotefusion.

In addition, as discussed in greater detail above, a passage can becreated through the pedicle toward the corresponding superior endplateof the vertebra. Such a transpedicular passage, can be initially createdusing a drill (e.g., cannulated drill) and subsequently enlarged and/orsafeguarded using one or more taps, cannulae (e.g., threaded cannulae)and/or the like, either with or without the use of a guidewire. As notedabove, a transpedicular opening or passage can advantageously provideaccess to the corresponding interbody or intervertebral space. Forexample, as discussed in greater detail herein, a pituitary-rongeur-likedevice or other sampling device can be advanced through thetranspedicular opening into the interbody space for biopsy and/orsampling of target tissue (e.g., disc material, endplate cartilage,vertebral bone, etc.). In other embodiments, a brush or other tissueabrading device can be advanced through one or more transpedicularpassages in order to selectively remove or abrade disc material and/orendplate cartilage/bone and/or otherwise prepare tissue positionedwithin or near the intervertebral space. Relatedly, one or morematerials (e.g., bone grafting agents, putty, nucleus filler materials,other fillers, expandable implants, other interbody implants, etc.) canbe delivered into a target interbody space via the transpedicularopenings.

According to some embodiments, a facet joint implant comprises a unitary(e.g., monolithic) structure or a multi-part design (e.g., having two ormore components). For example, as illustrated in FIGS. 18A and 18B, afacet joint implant 1000 can comprise two separate portions 1010, 1020that are configured to advantageously engage one another (e.g.,lockingly, non-lockingly, etc.) after implantation. As shown, a firstimplant portion 1010 can be configured to secure to one of the facetsurfaces F (e.g., inferior or superior), while the second implantportion can be configured to secure to the other facet surface F₂. Theopposing portions 1010, 1020 can be implanted into the adjacent facetsurfaces (e.g., chondral tissue, subchondral bone and/or the like) usingone or more protruding portions or features 1016, 1026, screws, otherfasteners and/or the like. As depicted in FIG. 18A, each portion 1010,1020 can be secured to the adjacent tissue using a single fastener orfeature 1026 or using two or more fasteners or features 1016, 1016′, asdesired or required.

With continued reference to FIGS. 18A and 18B, a facet joint implant1000 can comprise a ratchet-like configuration or design that permitsselective relative translation (e.g., proximal, distal, etc.) of theopposing portions 1010, 1020. For example, each of the portions 1010,1020 can comprise a plurality of teeth 1014, 1024 or other protruding orengagement members that are shaped, sized and otherwise adapted to mateor interdigitate with teeth or other protruding members along theopposite portion 1020, 1010. In some embodiments, the use of suchcomplementary teeth 1014, 1024 allows for proximal translation of theinferior facet of an upper vertebra relative to the superior facet ofthe immediately lower vertebra. Consequently, such a ratchet design canadvantageously permit for indirect decompression of the neural foramenand lateral recesses by translation of one implant portion 1010, 1020relative to the opposing portion 1020, 1010. Once a desired relativetranslation between the opposing portions of the implant has beenachieved, the portions can be advantageously secured to one anotherusing one or more permanent or releasable attachment method or devices,such as, for example, screws, tabs, pins, other fasteners, adhesives,welds and/or the like. The insertion of implant into the facet joint andany subsequent steps or procedures (e.g., distraction, fixation of oneportion of the implant to another portion, etc.) can be advantageouslyperformed using a minimally invasive approach.

In some embodiments, as depicted in FIG. 18B, a facet joint implantcomprises a generally oval or rectangular shape. The thickness of theimplant can be approximately 2 to 4 mm. Such a thickness canadvantageously permit the implant to fit within the plane of a facetjoint. Further, in some configurations, the implant extendsapproximately two-thirds of the way across the anterior-posteriordimension and/or the caphalad-caudad dimension of the facet joint. Inother arrangements, however, the shape, thickness, other dimension(e.g., length, width, etc.) and/or other characteristics of the implantcan vary, in accordance with a specific protocol or procedure. Forinstance, the facet joint implant can include a generally circular,other polygonal (e.g., triangular, hexagonal, octagonal, etc.) orirregular shape. In addition, the thickness of the implant can be lessthan about 2 mm or greater than about 4 mm. As noted above, in otherembodiments, a facet joint implant comprises a simpler unitary (e.g.,one-part or monolithic) structure.

Accordingly, in some embodiments, as discussed in greater detail herein,adjacent vertebrae can be immobilized relative to each other by fusionof adjacent facet surfaces, by fusion of adjacent endplate surfacesand/or by fusion systems that attach a first screw, fastener, implant orother device to another a second (or additional) screw, fastener,implant or other device. Thus, the facet surfaces of adjacent vertebraecan be fused to each other (e.g., with or without the assistance of oneor more implants). Facet fusion can be supplemented by one or moreadditional components of a fusion system, such as, for example, one ormore transpedicular screws inserted into in one or both of the vertebraecorresponding to the facet joint implant. In addition, transpedicularaccess into the patient's corresponding intervertebral or interbodyspace can be used to perform one or more procedures, such as, forexample, removal of disc and/or other native material, preparation ofendplates for fusion, delivery of grafting agents, otherfusion-promoting implants and/or the like. FIGS. 19A-19B illustratevarious views of adjacent vertebrae 10A, 10B that comprise facet jointimplants 1100. The illustrated embodiment of a fusion system alsocomprises one or more transpedicular screws 700 or other fasteners thatextend from the pedicles of the lower vertebra 10B into the interbodyspace 20. Such screws 700 can be inserted into passages or otheropenings that are created within the vertebra. As discussed in greaterdetail herein, such passages advantageously provide access (e.g., usingminimally invasive approaches) to a target interbody or intervertebralspace.

According to some embodiments, as illustrated in FIGS. 19A-19D, theportion of the facet joint implant 1100 adjacent the facet surface ofthe lower vertebra 10B is secured to the transpedicular screw 700 thatis routed through the lower vertebra 10B and into the intervertebralspace 20. The opposite portion of the facet joint implant 1100 (e.g.,the portion that is adjacent the facet surface of the upper vertebra10A) is secured to the upper vertebra 10A. For example, in theillustrated embodiment, this opposite portion of the facet joint implantis secured to the lamina of the upper vertebra 10A using a screw 1150(e.g., a lamina screw) or other fixation device or method. In someembodiments, each of the opposing portions of the facet joint implant1100 are fixedly (e.g., directly or indirectly) secured to thecorresponding screw or other fixation system. For example, the facetjoint implant section can include a ring or other extension throughwhich the corresponding screw (e.g., the transpedicular screw 700 or thelamina screw 1150) may pass. In other embodiments, one or moreintermediate connectors (e.g., rods, welds, tabs, etc.) are used toconnect the facet joint implant 1100 to the corresponding screw 700,1150 or other fixation system.

According to some embodiments, once the facet joint implant 1100 hasbeen properly secured to both the upper and lower vertebral members 10A,10B (e.g., using corresponding screws 1150, 700 or other fixationdevices), and the opposing portions of the facet joint implant 1100 havebeen properly secured to each other, relative movement between the upperand lower vertebral members 10A, 10B can be achieved, therebystabilization that portion of the spine, promoting fusion and/or thelike. In some embodiments, to further stabilize the spine, to providemore enhanced fusion and/or to provide one or more other benefits oradvantages, the fusion system illustrated in FIGS. 19A-19D can befurther supplemented. For example, in one embodiment, the fusion systemcan additionally include a second bone screw (e.g., pedicle screw P)positioned within the upper vertebra 10A, as illustrated in FIG. 20. Insuch a configuration, a rod R, connector or other fixation systemcomponent can be used to connect the transpedicular screw 700 positionedthrough the lower vertebra 10B to the pedicle screw P of the uppervertebra 10A.

In other embodiments, an implant (e.g., expandable implant, coiledimplant, inflatable implant, etc.), grafting material and/or any otherdevice or member can be positioned within the intervertebral space 20between the vertebrae 10A, 10B. In some embodiments, such devices and/ormaterials can be advantageously delivered to the intervertebral space 20through the transpedicular passage before the screw 700 is positionedtherethrough.

For any of the embodiments disclosed herein, it will be understood thatthe procedures performed on a first lateral side of the spine can beperformed on the opposite, second lateral side, either instead of or inlieu of the first lateral side. Thus, in some embodiments, a spinefusion system can include two transpedicular screws within the samevertebral member (e.g., one through each pedicle). Alternatively, asystem can include a transpedicular screw only through one pedicle, asdesired or required. Similarly, the fusion system can include facetjoint implants along one or both joints between two adjacent vertebrae.

Therefore, in reference to FIGS. 19A-19D, a minimally invasive approachcan allow the surgeon to perform a fusion procedure while accessing onlya small area of the patient's spine (e.g., the area posterior to one ormore pedicles). For example, access to such a relatively small area canallow the surgeon to create transpedicular openings from the pedicle tothe interbody space 20. As discussed herein, the resulting passage canpermit the surgeon to clean out the disc space and/other native tissuewithin the intervertebral space 20, deliver implants, grafting materialsand/or the like and/or perform one more procedures. At the same time,such access to the pedicle can allow the surgeon to insert atranspedicular screw 700. In addition, a facet implant 1100 can bepositioned within the facet joint and fixed to the adjacent vertebrae10A, 10B. As discussed herein with reference to FIGS. 18A and 18B, insome embodiments, the facet joint implant is configured to provide somedistraction between adjacent vertebrae before the position of theimplant 1100 becomes fixed.

As discussed above with reference to the bone screw embodimentsschematically illustrated in FIGS. 21A and 21B, the transpedicular screw700 can include a cortical thread pattern along its entire length. Inother embodiments, its thread pattern can be cortical at least along itsdistal end (e.g., where it passes through the cortical portion of theendplate 14B) and/or along its proximal end (e.g., where it passesthrough the cortical portion of the pedicle). Further, with reference toFIG. 20 below, the pedicle screw P that is positioned through the uppervertebra 10A can include a cancellous thread pattern along its distalend (e.g., where it is positioned within the cancellous interior portionof the vertebral body 10A) and a cortical thread pattern along itsproximal end (e.g., where it passes through the cortical portion of thepedicle). This can provide more secure fixation between the screws 700,P and the respective vertebral members.

In other embodiments, the facet joint implants and other fusionprocedures described herein can be combined with one or more otherstabilization systems or devices to provide an enhanced fusion systemand method. For example, facet joint fusion systems and techniques(e.g., with or without the use of facet joint implants) can be used inconjunction with pedicle screw and rod systems and/or the like. In someembodiments, such supplemental stabilization systems can include pediclescrews having a transpedicular orientation, as discussed in greaterdetail herein.

One embodiment of a spinal fusion system that comprises a transpedicularscrew 700 and a facet implant 1100 that are coupled or otherwise fixedlyconnected to one another is illustrated in FIGS. 19A-19D. The screw 700and the facet implant 1100 can be joined directly or indirectly (e.g.,using an interconnecting rod or other connection device). In someembodiments, with such a fusion system, the superior vertebra 10A issecured to the inferior vertebra 10B in a manner that can prevent orreduce the likelihood of relative movement. Thus, such a fusion systemcan maintain the two vertebrae is a generally fixed relationshiprelative to one another. The fusion between the two vertebrae can befurther enhanced if a transpedicular access is used to deliver animplant, grafting material and/or the like between the two adjacentendplates of the vertebral members 10A, 10B. Thus, in such embodiments,the vertebrae are fused both at the facet joint and the between theendplates, thereby providing for enhanced fusion.

In some embodiments, adjacent vertebrae are stabilized relative to eachother using rod or other interconnecting system. For example, asillustrated in FIG. 20, a transpedicular screw 700 inserted through thepedicle of the inferior vertebra 10B can be connected to a pedicle screwP positioned through the superior vertebra 10A. As with any otherembodiments disclosed herein, screws may be positioned on one or bothsides of the pedicles, as desired or required.

With continued reference to FIG. 20, the screw on the superior vertebra10A can include a typical pedicle screw P. In other embodiments,however, the upper screw P can comprise a transpedicular screw (e.g.,similar to the screw positioned through the pedicle of the inferiorvertebra 10B), as desired or required. This can be particularly helpfulif access is required to the intervertebral spaces located both aboveand below the superior vertebra 10A. Regardless of their exact position,orientation and/or other details, the screws 700, P can comprise tuliphead designs to receive a rod R or other securement system. In someembodiments, the fusion system illustrated in FIG. 20, which includestwo screws and a rod R or similar securement system, can also compriseone or more facet implants (such as, for example, the fusion implantsdisclosed herein with reference to FIGS. 18A-19D). Therefore, in such aconfiguration, adjacent vertebrae are maintained relative to each inone, two or three different manners—by the facet implant, fusion betweenadjacent endplates and the rod system extending between two or morepedicle or bone screws 700, P.

To assist in the description of the disclosed embodiments, words such asupward, upper, bottom, downward, lower, rear, front, vertical,horizontal, upstream, downstream have been used above to describedifferent embodiments and/or the accompanying figures. It will beappreciated, however, that the different embodiments, whetherillustrated or not, can be located and oriented in a variety of desiredpositions.

Although the subject matter provided in this application has beendisclosed in the context of certain specific embodiments and examples,it will be understood by those skilled in the art that the inventionsdisclosed in this application extend beyond the specifically disclosedembodiments to other alternative embodiments and/or uses of the subjectmatter disclosed herein and obvious modifications and equivalentsthereof. In addition, while a number of variations of the inventionshave been shown and described in detail, other modifications, which arewithin the scope of these inventions, will be readily apparent to thoseof skill in the art based upon this disclosure. It is also contemplatedthat various combinations or subcombinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the inventions disclosed herein. Accordingly, it should beunderstood that various features and aspects of the disclosedembodiments can be combine with or substituted for one another in orderto form varying modes of the disclosed inventions. Thus, it is intendedthat the scope of the subject matter provided in the present applicationshould not be limited by the particular disclosed embodiments describedabove, but should be determined only by a fair reading of the claimsthat follow.

What is claimed is:
 1. A method of fusing a first vertebra to a secondvertebra, said second vertebra being immediately adjacent and above thefirst vertebra, the method comprising: creating a passage from aposterior end of a pedicle of the first vertebra through a superiorendplate of the first vertebra, such that the passage extends into anintervertebral space located generally between the first and secondvertebrae; advancing a first bone screw through the passage, such that adistal end of the first bone screw extends at least partially into theintervertebral space; inserting a second bone screw through the secondvertebra; and attaching the first bone screw to the second bone screw.